This invention relates to multi-layer protective fabrics.
Garments used in fire fighting, for example, are made of fabrics that not only protect the fire fighter from the heat and flame of the fire, but also are waterproof and allow water vapor to pass from inside to outside the garment.
One such fabric is a laminate of a first layer comprising rayon and NOMEX (a fire-retardant, high-strength woven or non-woven fibrous material available from duPont) and a second layer of a micro-porous urethane film (e.g., P55FR available from Porvair of King's Lynne, UK). A micro-porous material is, for example, one that has pores sized to permit vapor molecules to pass, while blocking water molecules. The urethane film, which is normally flammable, is made fire retardant by loading it with fire retardant components during manufacture by a solvent process.
The National Fire Protection Agency (NFPA) recently changed its published standards to require fire fighting garments also to resist penetration by any of a list of chemicals sprayed in a specified way against the surface of the garment.
One attempt to meet the new standard involved coating the micro-porous urethane film of the fabric described above with a chemical resistant coating.